Seat recliner mechanism with spring coil actuator and creep eliminator feature

ABSTRACT

A recliner mechanism particularly adapted for motor vehicle seats is described. In accordance with this invention, the adjusted position of the seat back is controlled by using a recliner mechanism which includes a coil spring clutch which is selectively tightened or loosened around an actuator clutch drum. The upper recliner structure has a toothed quadrant which meshes with a recliner gear which rotates the rotating actuator clutch drum. A lever is employed to cause relative rotation between a pair of actuator cam plates which are connected to extending ends of a coil clutch spring. Movement of the actuator lever selectively causes the coil clutch spring to tighten or loosen around the actuator clutch drum. In accordance with another feature of this invention, a redundant positioning pawl is provided which prevents unrestrained motion of the upper recliner structure in the event of a failure or improper operation of the coil spring clutch actuator. The tendency of the recliner to &#34;creep&#34; when subjected to shock loading and vibration is eliminated by the use of a spring which biases the cam plates to the engaged position.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application Ser. No.753,047, filed July 1, 1985, and assigned to the assignee of thisapplication.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to a seat recliner mechanism and, moreparticularly, to a motor vehicle seat recliner mechanism which permitsthe angle of the seat back relative to the seat bottom to be varied asdesired by the seat occupant.

Many motor vehicles now feature seat recliner mechanisms which provideadded comfort and convenience for vehicle occupants. Numerous types ofseat recliner mechanisms are known to the prior art. For example, U.S.Pat. No. 4,372,610, issued to A. J. Fisher III et al on Feb. 8, 1983,described a recliner mechanism having a pair of meshing straight toothedracks. One of the racks is connected to the upper recliner structurethrough a quadrant component. Adjustment of the seat reclined angularposition is accomplished by changing the meshed position of one rackwith respect to the other. Patent application Ser. Nos. 589,229 filedMar. 14, 1984, and 594,742 filed Mar. 29, 1984, both assigned to theassignee of this application, relate to improvements in such reclinermechanisms. Patent application Ser. Nos. 602,370 filed Apr. 20, 1984,and 632,597 filed July 19, 1984, also assigned to the assignee of thisapplication, describe recliner mechanisms employing rotating gears forseat recliner position adjustment.

Although devices in accordance with the above-entitled patents andpatent applications perform satisfactorily, it is desirable to providefurther improvements in the design of seat recliner mechanisms. Many ofthe currently known seat recliner mechanism designs employ meshing teethfor position fixing which provide stepped changes in adjusted angularpositions so that fine adjustment of the reclined position isimpossible. it is therefore desirable to provide a seat reclinermechanism featuring continuously variable adjusted seat back angularpositions so that the user is not constrained to certain fixed angularpositions dictated by the recliner mechanism. Many currently known seatrecliner mechanisms produce annoying clattering or "ratcheting" soundsduring adjustment. It is therefore desirable to provide a seat reclinermechanism which provides silent operation and has smooth releasecharacteristics. Another desirable characteristic for a motor vehicleseat recliner is the ability to prevent unrestrained pivoting motion ofthe seat back in the event of failure or improper operation of the seatrecliner mechanism. Designers are further constantly striving for easeof production, low cost, simplicity, and reliability of all motorvehicle hardware components. Finally, a seat recliner mechanism shouldmaintain a desire reclined position despite being subjected to shockloadings and vibration.

The above described features for a motor vehicle seat recliner mechanismare provided in accordance with this invention. The recliner describedin detail below has a gear transmission coupled to a spring clutchactuator device which fixes the angular position of the seat back. In apreferred embodiment of this invention, a curved toothed rack isprovided which rotates with the upper recliner mechanism and meshes witha rotatable gear in the lower recliner mechanism. One or more additionalgears are employed to rotatably drive a drum. Fixing of the seatreclined position is achieved by providing, a coil spring clutch whichwraps around the drum, and an actuation mechanism which selectivelytightens or loosens the coil spring clutch around the drum to eitherrestrain or permit drum rotation. The recliner mechanism according tothis invention further includes a redundant positioning pawl which actsin conjunction with the coil spring actuator to restrain pivoting motionof the upper recliner structure. This redundant positioning pawlprevents unrestrained motion of the seat back in the event of failure orimproper operation of the spring clutch actuator. A creep eliminatorspring is provided which urges the coil spring clutch to be tightlywrapped around the drum to prevent the adjusted position of the seatrecliner mechanism from changing once it is adjusted to a desiredpostiion due to shock loadings and vibration.

The recliner mechanism according to this invention is usable for motorvehicle seats which are installed in two or four door type cars, as wellas for other types of motor vehicles. In four door car models, the frontseat back typically does not need to be folded forward to permit accessto the rear seat occupant area. However, for two door designs having arear seat occupant area, such provisions are usually necessary.Therefore, this invention is described in conjunction with an inertiasensitive seat back locking device according to prior art designs whichnormally permits the front seat back to be folded forward but acts toprevent folding when the vehicle is subjected to deceleration above apredetermined level. The inertia sensitive seat back locking systemdescribed in conjunction with this invention and various similar devicesare detailed by several of the previously mentioned U.S. patents andapplications.

Additional benefits and advantages of the present invention will becomeapparent to those skilled in the art to which this invention relatesfrom the subsequent description of the preferred embodiments and theappended claims, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the seat recliner mechanismaccording to the present invention;

FIG. 2 is a plan view of the seat recliner mechanism shown in FIG. 1;

FIG. 3 is a partial side elevational view of the seat recliner mechanismshown in FIG. 1 particularly illustrating the spring clutch actuator inan engaged position;

FIG. 4 is a side elevational view of the recliner shown in FIG. 1particularly showing the spring clutch actuator in a released position;

FIG. 5 is an exploded pictorial view of the components of the springclutch actuator according to the invention;

FIG. 6 is a cross-sectional view taken along line 6--6 of FIG. 3particularly showing the rivet used for restraining the coil clutchspring ends; and

FIG. 7 is a view taken in the direction of arrow 7 in FIG. 1particularly showing the creep eliminator spring in accordance with thisinvention.

DETAILED DESCRIPTION OF THE INVENTION

A motor vehicle seat recliner mechanism according to this invention isshown assembled in FIGS. 1 through 4 and is generally designated byreference character 10. The embodiment of recliner mechanism 10described herein by the accompanying Figures is intended to bepositioned at the lefthand side of a motor vehicle's driver's seat. Arecliner structure useful for a front passenger's seat would preferablyemploy components which are mirror image replications or are orienteddifferently than those described herein. Seat recliner mechanism 10includes lower recliner structure 12 which becomes attached to a seatbottom frame (not shown). Upper recliner structure 14 becomes attachedto a seat back frame (now shown) and is adapted to pivot with respect tolower structure 12 about pivot pin 16. Lower recliner structure 12 isfabricated by attaching two plates, inner lower recliner plate 18 andouter lower recliner plate 20. These plates are attached together byrivets or by welding and define a space therebetween which accommodatesadditional components which are described below. Upper reclinerstructure 14 is similarly fabricated by attaching two plates, innerupper recliner plate 22 and outer upper recliner plate 24. These platesare also formed to define a space therebetween.

Quadrant 26 is rotatable about pivot pin 16. The position of quadrant 26establishes the angular position of upper recliner structure 14 withrespect to lower recliner structure 12, and therefore between the seatback and bottom. As shown by the Figures, quadrant 26 includes arcuateslot 28. Pin 30 is attached to lower recliner structure 14 and travelswithin slot 28 to limit the maximum extent of the angular range ofadjustment of the upper recliner structure. For four door style motorvehicles, or for other applications wherein a seat back foldingmechanism is unnecessary, quadrant 26, or its functional equivalent maybe fastened directly to upper recliner structure 14, or can be madeintegrally therewith.

In accordance with a principal feature of this invention, quadrant 26includes curved toothed rack 32 along its lower edge. Toothed rack 32 isformed along a circular path having its center about pivot pin 16. Firstrecliner gear 34 is attached to lower recliner structure 12 and mesheswith toothed rack 32. Preferably, first gear 34 includes a steppedexternal surface forming gear sections 36 and 38 having differingdiameters. As shown in FIG. 1, gear section 36 has a smaller diameterthan that of section 38. First gear 34 is rotatably attached to thelower recliner structure 12 by permitting pin 40, which is fixed to thegear, to rotate in bores 42 of lower recliner structure plates 18 and20. First gear 34 is positioned so that toothed rack 32 meshes with gearsection 36, thereby causing rotation of the gear as the angular positionof the quandrant 26 (and hence the upper recliner structure 14) ischanged with respect to lower recliner structure 12. Rotational biasingis applied to upper recliner structure 14 through the use of torsionspring 44 having an inner end which engages with slot 46 of pin 40. Aradially outer end of torsion spring 44 is grounded to the lowerrecliner structure 12 at any convenient point. This rotational biasingenables the seat occupant to easily and conveniently adjust the seatback position by pushing against the seat back when the actuator isreleased until the desired angular position is reached.

Second recliner gear 48, like first gear 34, is journalled for rotationwithin lower recliner structure 12 and rotates about pin 50 within lowerrecliner structure 12. Second recliner gear 48 defines a pair of gearsections 52 and 54 of differing diameters wherein section 54 has alarger diameter than diameter section 52. Diameter section 52 of secondrecliner gear 48 meshes with section 38 of first recliner gear 34, asbest shown in FIGS. 1, 3 and 4.

The spring clutch actuator of recliner 10, best shown in Figure 5,includes actuator clutch drum 56 which is journalled for rotation withinlower recliner structure 12 about pivot pin 58. Actuator clutch drum 56defines a relatively smooth cylindrical exterior surface (although itmay be roughened to achieve the desired frictional characteristics).Actuator clutch drive gear 60 is fixed for rotation with actuator clutchdrum 56 (or is integral therewith) and meshes with section 54 of secondrecliner gear 48. The meshing relationship of gears 34, 48, and 60provides a transmission which minimizes the restraining torque necessaryupon actuator clutch drum 56 needed to restrain motion of upper reclinerstructure 14 is response to high torque loads exerted on the upperrecliner structure.

Rotation of actuator clutch drum 56 is selectively controllable byemploying coil clutch spring 62 which wraps around drum 56 and includesa pair of extending pigtail ends 64 and 66. By changing the relativeangular positioning of ends 64 and 66, spring 62 is caused toselectively frictionally engage or disengage actuator clutch drum 56.When ends 64 and 66 are moved to increase the angle of wrap of coilclutch spring 62 around actuator clutch drum 56, the diameter of thespring decreases so that it tightly engages the drum and restrains itsrotation by friction. Conversely, when the angle of wrap of coil clutchspring 62 around clutch drum 56 is increased by movement of ends 64 and66, the spring loosens its grip on the drum and it may be rotatedfreely. Spring 62 is wound so that it normally tightly wraps around drum56 in the absence of forces exerted on ends 64 and 66.

The actuation system which controls the angular relationship betweenends 64 and 66 of coil clutch spring 62 will now be described. A pair ofactuator cam plates 72 and 74, each having bores 76 and 78 respectively,are journalled for relative rotation about pivot pin 58 or clutch drum56. Actuator cam plates 72 and 74 include spring engaging arms 80 and 82and actuator lever arms 84 and 86. Rivets 92 and 94 which include slots68 and 70 receive spring pigtal ends 64 and 66. FIG. 6 shows rivet 92 indetail and is exemplary of both rivets. Gripper blocks 102 are providedto firmly engage spring ends 64 and 66, and have a roughened surfacewhich bites into the spring ends. When rivet 92 is deformed as shown inFIG. 6, gripper block 102 securely engages spring end 64. An additionalslot 96 is provided within lower recliner structure 12 to preventinterference with rivet 94.

The relative angular positioning of actuator cam plates 72 and 74, andhence ends 64 and 66 of coil clutch spring 62, is controlled throughmovement of actuator lever 106 which is pivoted for rotation withrespect to lower recliner structure 12 about pivot pin 108. Actuatorlever 106 is biased toward a normal engaged position shown in FIG. 1through use of coil torsion spring 110. Drive pin 112 is attached toactuator lever 106 and is caused to move along a circular path asactuator lever 106 is rotated. Drive pin 112 moves within a pair of camslots 114 and 116 defined by actuator cam plate arms 84 and 86. Movementof actuator lever 106 between a disengaged and engaged position isdepicted in detail in FIGS. 3 and 4.

FIG. 3 illustrates the normal engaged position of the components whereinthe position of upper recliner structure 12 is fixed. In this position,drive pin 112 is acting on cam slots 114 and 116 and permits cam plates72 and 74 to be moved in a direction which wraps pigtail ends 64 and 66around actuator clutch drum 56 which decreases the diameter of coilclutch spring 62 causing it to firmly frictionally engage actuatorclutch drum 56. Since spring 62 normally tightly wraps around drum 56,drive pin 112 does not forceably cause the spring to restrain motion ofthe drum. In a well-known manner, such clutch springs tend to increasetheir degree of frictional engagement with the associated frictionsurface as rotational torque is applied since such frictional engagementfurther tends to increase the contact force between the spring andsurface and therefore the frictional restraining force provided.Therefore, the interaction of coil clutch spring 62 and actuator drivedrum 56 comprises a self-energizing clutch mechanism. Cam slots 114 and116 are conformed to provide for a slight degree of lost motion whichoccurs as spring 62 deforms in response to applied torques. For example,with respect to the orientation of elements shown in FIG. 3, as themotor vehicle user exerts his or her weight against the seat back andagainst the upper recliner structure 14, a counterclockwise directedtorque load is applied about pivot pin 16. This load translates into aclockwise directed torque applied to actuator clutch drum 56. If suchtorque is sufficiently great, deformation of coil clutch spring 62results. In this condition, actuator cam plate 72 is loaded to restrainrotation and transfers load through drive pin 112. Actuator cam plate 74is unloaded (since spring 62 normally tightly wraps around drum 56) andis provided with the ability to move rotationally a small extent inorder to prevent it from exerting a force on spring end 66 which wouldtend to loosen the grip of coil clutch spring 62 on actuator clutch drum56. Similarly, when an oppositely directed torsional load is applied toactuator clutch drum 56, actuator cam plate 72 is permitted to moveslightly with respect to drive pin 112.

FIG. 4 shows the position of the components when actuator lever 106 isrotated in a counterclockwise (released) direction. In this position,drive pin 112 interacts with cam slots 114 and 116 to rotate pigtailends 64 and 66 angularly toward one another, which has the effect ofincreasing the effective diameter of coil clutch spring 62, therebyreleasing actuator clutch drum 56 for rotation and enabling a changingin the angular positioning of the upper recliner structure 14.

With particular reference to FIGS. 3, 4, and 7, seat recliner mechanism10 further includes coil torsion type creep eliminator spring 176 whichis positioned by pin 178 between inner and outer lower recliner plates18 and 20. Creep eliminator spring 176 has a pair of hook shaped ends180 and 182 which act upon actuator cam plates 72 and 74, respectivelyto urge the cam plates in a direction of tightening the wrap of coilclutch spring 62 around actuator clutch drum 56. Use of spring 176 hasbeen found to eliminate "creep" or the tendency of drum 56 to slipwithin coil clutch spring 62 when recliner mechanism 10 is subjected torepeated loadings. When actuator lever 106 is moved to the releasedposition shown in FIG. 4, creep eliminator spring 176 is overcome topermit movement of cam plates 72 and 74 to their released position.

Seat recliner mechanism 10 according to this invention further providesa redundant positioning feature which acts to restrain uncontrolledmotion of upper recliner structure 14 in the event of a failure orimproper operation of the coil spring actuator. Redundant positioninglever 120 is rotatably pivotable about pivot pin 50 and includes arm 122which contacts drive pin 112 and further defines arm 124. Redundantpositioning pawl 126 is pivotably connected to lower recliner structure12 and includes a pair of ends 128 and 130. End 130 engages arm 124causing pawl 126 to be moved between quadrant engaging and quadrantdisengaging positions. Redundant positioning pawl 126 is resilientlybiased toward a quadrant engaging position by coil torsion spring 132.FIG. 3 illustrates the position of the components in the normal engagedposition. In this condition, end 128 of redundant positioning pawl 126is positioned in the path of motion of quadrant 26 such that it can bemoved only to the position shown in FIG. 3 and not to a further rotatedposition, thus preventing unrestrained motion in the event of failure ofthe spring clutch actuator system. The user may rotate the upperrecliner structure 14 to a more reclined position only if redundantpositioning pawl 126 is moved out of the path of motion of quadrant 26which occurs when actuator lever 160 is moved to the disengaged positionshown in FIG. 4. In this position, the interaction between drive pin 112and arm 122 of lever 120 causes the lever to be moved in a clockwisedirection, moving arm 124 to engage with end 130 of pawl 126, causing itto be moved counterclockwise and out of the path of motion of quadrant26. The angular position at which redundant positioning pawl 126 engagesquadrant 26 corresponds to a reclined angular position which will permitthe driver to continue operation of the associated motor vehicle,thereby enabling it to be driven until repairs to recliner 10 can beundertaken or until normal functioning of the mechanism is restored.

For use in two-door car models, motor vehicle seat recliner 10 accordingto this invention further features inertia sensitive actuator 136 whichprevents forward rotation of the seat back during conditions of suddendeceleration of the associated motor vehicle. Inertia sensitive actuator136 of vehicle recliner 10 interacts with quadrant 26 and responds tovehicle deceleration to prevent forward rotation of the seat back.Actuator 136 includes upper weighted section 138 and lower engagingportion 140 with bore 142 therebetween. Upper weighted section 138includes weights 144 and 146. Pivot pin 148 is attached to upperrecliner structure 14, passes through bore 150, and cooperates to form alow friction bearing permitting free rotation of actuator 136. Theactuator 136 is configured such that its centroid of mass (center ofgravity) lies above pivot pin 148 so that, upon vehicle deceleration,actuator 136 is caused to rotate in a clockwise direction with respectto the orientation shown by FIG. 1. Engaging portion 140 of actuator 136supports engaging pin 152. Engaging pin 152 is retained in associationwith engaging section 140 since it is trapped between locally deformedportions 154 and 156 (not shown) which forms slots 158 and 160 (notshown) respectively within upper recliner plates 22 and 24. Quandrant 26includes a notched upper portion defining stop surface 162. Therefore,when a predetermined level of vehicle deceleration is sensed by actuator136, the forward movement of upper recliner structure 14 is limited dueto engagement between engaging pin 152 and stop surface 162. Forwardmovement of upper recliner structure 14 in this situation is preventeddue to engagement of engaging pin 152 with stop surface 162 of quadrant26 and the edges of slots 158 and 160. Under normal circumstances, theseat back may be freely rotated forward since engaging pin 152 ispermitted to escape engagement with surface 162. Such escapement isprovided by placement of the centroid of mass (center of gravity) ofactuator 136 such that the actuator is normally biased by gravity in acounterclockwise (disengaging) direction.

In order to provide enhanced reliability of engagement between actuator136 and stop surface 162, quadrant surface 164 is provided whichcontacts the actuator so that is is biased in an engaged position whenthe seat back is in its rearmost position. Slight forward rotation ofthe seat back relieves this bias and enables actuator 136 to eithercause engaging pin 152 to escape engagement with stop surface 162, orengage with the stop surface in response to vehicle deceleration. Theabove description of inertia sensitive actuator 136 is for illustrativepurposes only. Many designs for such mechanisms are known to the art andcould be employed in conjunction with this invention with equal success.

An emergency releasing mechanism is provided to enable rear seatoccupants to extract themselves from the vehicle in the event of failureof the inertia sensitive components of the seat recliner or in the eventthat vehicle inclination causes the hinge mechanism to latch. Therefore,release actuator 168 is provided having a rearwardly projecting portion170 which may be rotated about pivot pin 172 by the rear seat occupantsso that inertia sensitive actuator 136 is caused to rotate in acounterclockwise position about pivot pin 148, thereby withdrawingengaging pin 152 from engagement with stop surface 162 and permittingthe seat back to be folded forward.

While the above description constitutes the preferred embodiments of thepresent invention, it will be appreciated that the invention issusceptible to modification, variation and change without departing fromthe proper scope and fair meaning of the accompanying claims.

What is claimed is:
 1. A seat recliner mechanism for supporting a seatback and a seat bottom which permits the angle therebetween to becontrollably varied comprising:a lower recliner structure supportingsaid seat bottom, an upper recliner structure supporting said seat back,a first pivot rotatably attaching said lower recliner structure to saidupper recliner structure, a toothed rack operatively connected to one ofsaid upper or lower recliner structures, gear means carried by the otherof said upper or lower recliner structures for engaging said toothedrack and controlling the positioning of said toothed rack, an actuatorclutch drum carried by the other of said upper or lower reclinerstructures and rotatably driven by said gear means, a unitary coilclutch spring wrapping around said actuator clutch drum, said coilclutch spring having first and second spring ends, first spring engagingmeans carried by the other of said upper or lower recliner structuresfor engaging said first spring end, second spring engaging means carriedby the other of said upper or lower recliner structures for engagingsaid second spring end, actuation means carried by the other of saidupper or lower recliner structures for producing relative movementbetween said first and second spring engaging means thereby moving saidfirst and second spring ends from an engaged position in which said coilclutch spring frictionally engages said clutch drum such that said firstspring engaging means restrains rotation of said actuator clutch drum ina first rotational sense and said second spring engaging means restrainsrotation of said clutch drum in a second rotational sense wherein therelative angular positioning between said lower and upper reclinerstructures is established, to a disengaged position in which said coilclutch spring frictionally disengages said actuator clutch drum whereinthe relative angular positioning between said lower and upper reclinerstructures is adjustable, and spring means urging said spring engagingmeans to said engaged position.
 2. The seat recliner mechanism accordingto claim 1 wherein said spring means is a coiled torsion spring having apair of extending arms which act upon said spring engaging means.
 3. Theseat recliner mechanism according to claim 2 wherein said spring meansis supported within said lower recliner structure by a pin.
 4. The seatrecliner mechanism according to claim 1 wherein said first and secondspring engaging means comprise first and second cam plates which arerotatable about the axis of rotation of said actuator clutch drum, andsaid cam plates each having spring engaging arms which engage said coilclutch spring ends.
 5. A seat recliner mechanism supporting a seat backand a seat bottom which permits the angle therebetween to becontrollably varied comprising:a lower recliner structure supportingsaid seat bottom, an upper recliner structure supporting said seat back,a first pivot rotatably attaching said lower recliner structure to saidupper recliner structure, a toothed rack operatively connected to saidupper recliner structure, a first gear carried by said lower reclinerstructure meshing with said toothed rack, a second gear carried by saidlower recliner structure meshing with said first gear, a coil springclutch actuator including an actuator clutch drum carried by said lowerrecliner structure, an actuator clutch drum drive gear meshing with saidsecond gear, said first gear said second gear and said actuator clutchdrive gear providing a gear transmission which produces a torque appliedto said actuator clutch drum which is less than that applied to saidfirst gear by said toothed rack, and a coil clutch spring wrappingaround said actuator clutch drum, sid coil clutch spring having firstand second extending ends, first and second cam plates rotatable aboutthe axis of rotation of said actuator clutch drum, said actuator camplates each having spring engaging arms engaging said coil clutch springends and having actuator lever arms defining cam surfaces, a movableactuation lever having a drive pin which interacts with said actuatorlever arm cam surfaces to move said actuator cam plates betweenpositions of frictional engagement and disengagement of said coil clutchspring with said actuator clutch drum, spring means urging said camplates to said engaged position, and a redundant positioning pawlmovable between positions of engagement and disengagement with saidtoothed rack in response to movement of said actuator lever forrestraining angular movement of said upper recliner structure withrespect to said lower recliner structure in the event of failure orimproper operation of said coil spring clutch actuator.
 6. The seatrecliner mechanism according to claim 5 wherein said spring means is acoiled torsion spring having a pair of extending arms which act uponsaid cam plates.
 7. The seat recliner mechanism according to claim 6wherein sand spring means is supported within said lower reclinerstructure by a pin.